1. Field of the Invention
The present invention relates to an apparatus for cutting ice. More specifically, the invention relates to an apparatus for cutting ice using a rotating disc positioned approximately one inch beneath an evaporator vessel tube sheet, particularly in connection with commercial and industrial ice making machines.
2. Related Art
Rotating ice cutter discs of ice making machines are built so that the discs have several cutter knives or blades mounted on the top surface of the disc. The blades are positioned in such a way that the cutting edge is adjusted to rotate just slightly, approximately one sixteenth of an inch, below the bottom face of the evaporator tube sheet. The blades cut off segments of the vertical ice pieces which drop onto the rotating disc. The ice maker works by having water circulating inside tubes in the evaporator vessel. The ice freezes on the inside wall of the tubes until only a small hole approximately one quarter inch in diameter remains. When a reverse cycle defrost is initiated, the defrosted vertical ice shafts defrost from the tubing walls and drop vertically onto the rotating disc spaced which is approximately one inch beneath the bottom face of the evaporator vessel tube sheet.
The rotating disc is designed in such a way as to have a hole or slot approximately the full size of the cutter knife in the disc under each knife for the ice that is cut to fall through as it is cut off, after which it slides down a chute to be discharged from the machine.
The evaporator vessel and the defrosted vertical ice pieces, in many cases, were up to 15 feet in length. The ice had to be cut into lengths of one and half inches. This required a substantial portion of the total ice making cycle just for the xe2x80x9cchop time.xe2x80x9d During this chop time, the hot gas was also putting heat back into the evaporator which would unnecessarily extended that portion of the cycle and reducing the efficiency and capacity of the system. The heat that went in had to be pulled back out of the evaporator during the subsequent freezing cycle.
The vertical ice pieces must remain practically fixed at the moment they are being cut to give a xe2x80x9csquarexe2x80x9d cutting face to the pieces. When the ice starts to fall again after each cut, this intermittent motion further adds to the time required for the cutting cycle.
The ice making is limited to the maximum RPM that the ice maker can turn the rotating disc by the maximum permissible peripheral speed of the disc before shattering of the ice cubes occurs.
Accordingly, there is little that can be done to shorten the total cycle time and improve efficiency other than to shorten defrost time and xe2x80x9cchop time.xe2x80x9d But since the defrost is also continuing during the xe2x80x9cchop time,xe2x80x9d it has been determined that one can shorten the total cycle time 2 minutes for every 1 minute one shortens the defrost and xe2x80x9cchop time.xe2x80x9d This is due to the equal amount of freeze time which must be added to the cycle to compensate for any extension of the harvest cycle and the extra heat added back into the vessel that must be removed during the following freeze cycle.
In view of the stated operating criteria, about the most effective thing that can be done is to reduce total cycle time required. However, with the conventional cutter knife, to minimize the time that the ice is delayed in dropping after being cut would be difficult since the ice has to ride across the flat top of the conventional cutter knife that covers the hole in the rotating disc, before hitting the flat top surface of the rotating disc.
It is the solution to the foregoing and other problems to which the present invention is directed.
It is therefore a primary object of the invention to provide a rotating disc with a sloped cutter knife for reverse cycle harvest in an ice maker.
Another object of the invention is to provide the rotating disc with an outer edge and a round flat top surface having a plurality of triangularly shaped through holes.
It is another object of the invention to have a plurality of cutter knives with triangularly shapes, each securely fastened to the round flat top surface of the disc and fixedly positioned to nearly cover the triangularly shaped through holes.
Another object of the invention is to ensure each of the triangularly shaped through holes forms a slot, and the formed slot extends nearly from the center mounting hole to the outer edge of the rotating disc.
It is another object of the invention to provide each the plurality of cutter knives with a raised portion, and the raised portion being positioned over the triangularly shaped hole and parallel with the slot.
Another object of the invention is to provide a plurality of cutting edges for cutting ice in the ice maker, wherein each cutting edge forms the raised portion of the cutter knives and is parallel with each corresponding slot.
A further object of the invention is to provide a back edge for the plurality of cutter knives which extends nearly from the center mounting hole to the outer edge of the rotating disc.
It is an object of the invention to make the back edge of each of the cutter knives flush with the round top surface and securely fastened to the round top surface.
Another object of the invention is make, on each of the cutter knives, a sloping surface which connects each cutting edge to each back edge.
These and other objects of the invention are achieved by the present invention which is directed to a plurality of cutting knives or blades mounted on a rotating disc for cutting ice in an industrial ice maker.
More specifically, the rotating disc has a center mounting hole for rotatably mounting the disc in the ice maker and an outer edge. The round flat top surface of the disc includes a plurality of triangularly shaped through holes. The base of each of the triangularly shaped through holes is equally spaced from center mounting hole and positioned near the outer edge. The invention is directed to a plurality of cutter knives having triangular shapes. Each of the plurality of cutter knives is securely fastened to the round flat top surface and fixedly positioned to nearly cover each of the triangularly shaped through holes. A space or slot is formed in the gap or portion not covered by the cutting knife. The formed slot extends nearly from the center mounting hole to the outer edge. There remains a raised portion which includes the cutting edge. The rest of the cutter knife is a sloping surface which is connected or welded to the top surface of the rotating disc. As the ice falls, it is cut. The cut portion falls through the slot and down a chute. The remaining portion slides down the sloping surface and, upon hitting the top surface of the rotating disc, the ice is ready to be cut.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.